Advancements in personal protective equipment (PPE) have enabled firefighters to operate and survive in relatively extreme conditions when fighting fires within a building. However, the personal protective equipment may not provide a firefighter with adequate protection when the firefighter is exposed to a structural failure within a building. In some cases, structural failures can trap the firefighter within a building and/or can seal off potential exit paths.
To determine if a building is becoming unstable, firefighters generally use a variety of physical observations. For example, firefighters may rely on physical observations of the building such as observing bowed walls or feeling for softness in a floor area. Such physical observations, however, may be unreliable and are often limited by the physical signs that are visible to the firefighters. As a result, firefighters may lack knowledge of a potential structural failure which may result in the firefighter being injured, or to run out of air after becoming entangled or disoriented as an indirect result of a structural collapse.
Electrically connected heat sensors may be used. Such sensors are expensive, however, which limits their widespread application. In addition, the size and wiring required for such head sensors may make it impractical to install such sensors on trusses, cross-members, and beams in sufficient quantity to detect when dangerous heat impinges on the structural members. Battery powered sensors may be used for applications in which it is impractical to use wired sensors (due to the presence of moving parts which make it difficult to maintain electrical connections). Current battery operated devices may also be undesirable, however, because batteries typically require replacement at periodic time intervals (6 months, 1 year). Even for cases in which a battery may last extended periods (up to 7+ years) current battery powered devices still can be undesirable because the sensor may be disposed in a location that is difficult to access in order to change the battery.